Check valves are valves that allow fluid flow in one direction therethrough and prevent flow in the opposite direction. They are widely used in a range of applications, for example in air conditioning systems, for example in aircraft air conditioning systems.
Check valves commonly include a pair of valve elements or flappers located at an opening in a valve housing. The flappers are hingedly supported on a hinge pin mounted to the valve housing for rotation between a closed position in which they lie across and close the opening, preventing fluid flow through the opening in one direction and an open position in which, under the pressure of a fluid (gas or liquid) on one side of the check valve, the flappers rotate from their closed positions so as to allow the fluid to flow through the valve in the opposite direction.
In known check valve arrangements, a stop is provided to limit the rotational movement of the flapper elements as they open. Typically, the stop comprises a stop pin which is mounted to posts arranged on opposed sides of the valve housing opening. The stop pin is spaced from the opening such that when the flappers open, they engage the stop pin.
In one known check valve arrangement, as in US 2017/0204981 A1, each flapper comprises a primary flapper element and a secondary flapper element, each pivotally mounted to a hinge extending across the valve. The primary flapper element comprises a flapper opening therethrough and the secondary flapper element is pivotally mounted to the hinge pin such that it may rotate relative to the primary flapper element for opening or closing the flapper opening.
The present disclosure relates to a check valve of this general construction having a modified stop arrangement.